1. Field of the Invention
The invention generally relates to a continuous anesthesia nerve conduction apparatus, system and method thereof, and more particularly to a method and system for use in administering a continuous flow or intermittent bolus of anesthetic agent to facilitate a continuous or prolonged nerve block.
2. Discussion of the Related Art
Currently, regional anesthesia techniques have been employed to selectively anesthetize a nerve or groups of nerves to provide pain relief to patients following a medical-surgical procedure or trauma. Anesthetic agents, such as local anesthetic medication, are administered in close proximity to nerve(s) that innervate the affected region of the body. These nerves are located deep within the tissues and a hollow bore hypodermic needle is used to deliver the anesthetic medication to the nerve(s).
In continuous regional anesthetic procedures, in lieu of a needle, a catheter and needle are inserted adjacent to the nerve(s). The needle is removed after the catheter placement, and the catheter may be left in position for several days so that anesthetic medication can be repeatedly or continuously delivered to the targeted nerve(s). These nerve blocks are only efficacious if the anesthetic medication can be delivered consistently in close enough proximity to the nerve(s) so as to impart its action on the nerve(s).
U.S. Pat. No. 5,976,110 discloses an epidural needle that can be coupled to a nerve stimulator. The nerve stimulator is configured to provide an electrical current that activates the targeted nerve(s) as the needle gets into close proximity of the nerve(s). An epidural catheter is inserted through the lumen of the epidural needle and advanced until the distal tip extends several centimeters past the distal tip of the needle. The epidural catheter is placed without any visualization aid and is assumed to be in close enough proximity to the targeted nerve due to the needle tip position.
U.S. Pat. No. 6,456,874 discloses an epidural catheter configured to emit an electrical impulse. Placement of the catheter tip and confirmation of the catheter tip placement is obtained by stimulating the targeted nerve(s) via the nerve stimulator.
In addition to the use of peripheral nerve stimulation for nerve localization, ultrasound imaging has become a common method to position needles and catheters in close proximity to nerve(s).
The related art has a number of disadvantages. The ultrasound probe is best managed by the operator of the needle and/or catheter. As such, to maintain real-time imaging, one of the operator's hands needs to be occupied handling the ultrasound transducer. However, the procedure is difficult with the related art devices as both hands are required for advancing a catheter through the needle. Therefore, during this procedure the ultrasound probe must be put down and the visualization at that point is lost.
Alternatively, another clinician is required or some sort of mechanical holding means may be utilized. These alternatives both have disadvantages. The ultrasound image is a two-dimensional image with an image plane of typically less than one millimeter. The mechanical holding devices, i.e., an articulating probe holder often is not effective because patient movement can cause the image to distort or deviate, thereby preventing reliable real-time imaging of the catheter exiting the needle and also preventing visual confirmation of the position of the catheter tip. Moreover, the related art catheter devices frequently employ Touhy tipped needles that tend to cause the catheter to curve away from the tip of the needle and out of the two-dimensional visualization plane as the catheter exits the needle. Therefore, images of the needle with the catheter exiting the needle are not typically obtained and the relationship to the targeted nerve(s) is not conclusively obtained.
Another disadvantage of the related art is the need for two hands to manage the catheter advancement, as both hands require sterile gloves and sterile procedural adherence. Thus, the ultrasound device will need to be sterile, which requires additional setup such as sterile sleeves for the ultrasound probe, sterile ultrasound gel, extensive draping, and additional personnel. This additional setup adds to the complexity, inefficiency, timeliness, and cost of clinicians performing this technique.
The related art catheters themselves also have disadvantages. For example, in order for the needle to be withdrawn while trying to maintain the catheter in place, the catheter needs to be about twice the length of the needle. This added length makes the catheter unwieldy, expensive, and difficult to use. The catheter also requires a lubricious exterior so that it will easily slide through the needle. The lubricious exterior of the catheter makes it difficult to adhere to the skin of the patient, which leads to easy dislodgement from its position adjacent to the nerve(s).
In addition, passing the catheter through the lumen of a large bore needle, the catheter's diameter is such that it is smaller than that of the puncture made by the needle through the tissue. The catheter diameter size being smaller than the needle can lead to leakage of medication at the insertion site during medication infusion, increasing the chance of catheter dislodgement.
There is a need for an improved continuous anesthesia nerve conduction apparatus, system and method that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.